After two years of development, Game Closure is launching a software development kit to enable game creators to marry HTML5 with Javascript to create fast-moving web games that incorporate graphics acceleration.

In the past, gamemakers have tried to embrace HTML5, the new lingua franca of the web, to create games that can run on any platform. That potentially saves a lot of money, but HTML5 runs too slow without graphics acceleration via a graphics processing unit, or GPU.

Michael Carter, the chief executive of Game Closure, said the advantage is that its kit enables quick and easy development with GPU-backed native performance. In short, it leads to fast games that are easy to make.

“Developers write Javascript, we compile to native, and it’s not a wrapped web view,” Carter said in an email. “Our engine has backed dozens of games, millions of users, and we’ve hit the top-10 charts in 20-plus countries around the world.”

Today, Carter’s company is releasing the Game Closure DevKit for everyone to build mobile games. The kit is free and open source. Carter said developers will use the kit to create mobile games much more quickly, cheaply, and of higher quality. He said the games will automatically be suitable for worldwide publication, run on every platform that matters, and will be optimized for quick reaction to monetization and user metrics after launch.

“This is a technology that empowers small teams to build top 10, worldwide games for Android and iOS simultaneously,” Carter said. “We are making this technology available to the world for free as open source so that everyone can contribute features and bug fixes while selling commercial games on the app stores without any licensing or royalty fees to Game Closure.”

Carter said that his company wants developers to build fun games without worrying about a buggy, crash-prone tech stack — translating to dozens of languages, or porting and rewriting for multiple phones, operating systems, and stores.

“There’s simply no reason that mobile-game development should be this hard,” he said. “The worst part now is that the vast majority of studios fail before they even get to the hard part: moving quickly to react to user data and increase monetization through quick game updates around content and in-app purchases. The companies that are lucky enough to make it that far often miss their opportunity because they can’t move quickly enough to fully monetize a growing user base.”

Carter said his kit solves all of those problems, and his comapny is making it free to expand its community as fast as possible.

He said that Game Closure developers regularly release high-quality, polished games to the store after two or three weeks of development.

“HTML5 and Javascript have the most mature development environments, period,” he said. “Every year Google, Apple, Firefox, Microsoft, and others pour millions of dollars into developing a toolset. From editors, faster scripting engines, memory profilers, debuggers, and language features, you can depend on an incredibly healthy ecosystem of HTML5 developer tools. There is no disputing that the web application development stack is one of the most robust, mature, and familiar in the software industry.”

Game Closure will develop paid products in the future. The company was founded in 2011 and raised $12 million from Highland, Greylock, Benchmark, Yuri Milner, Matt Ocko, Joi Ito, SV Angel, and Felix Shpilman.